Senator Bernie Sanders (I-VT) released his Medicare For All bill this week with an impressive 16 co-sponsors, and it contained one very interesting section that has been mostly overlooked.

Roughly one-fifth of the bill is dedicated to the creation of a very detailed “Medicare Transitional Plan.”

Under Sanders’ bill, Americans would be phased-in to a new Medicare plan over the course of 4 years. Children would be enrolled the first year and the Medicare age would lower to 55. It would then lower by 10 years, each year, for the next three years. After that, everyone would be enrolled.

The Medicare Transitional Plan would be available for anyone who doesn’t yet qualify for the new Medicare plan during those 4 years. It would have an actuarial value of 90 percent, meaning individuals would be responsible for 10 percent of the costs of all covered health care benefits. This would be classified as “Platinum” coverage on the exchanges. It would be better suited for nonseniors and includes a series of subsidies that make it truly affordable for everyone.

A surprising amount of work when into this one section of the bill since, if the legislation was adopted in its entirety, it would exist as an option for 4 years. It is a smart policy addition because if the private insurance market unraveled while the Medicare age was lowered, there should be a backup to provide good coverage for those who cannot yet enroll.

Considering it’s a very short-term stopgap, it is remarkably well thought out. The section is different in style from the rest of Sanders’ bill, and during the bill’s unveiling, Senator Kirsten Gillibrand (D-NY) took credit for its inclusion.

“One part of the bill that I worked with my colleagues to put in was the ability for every American to buy into a non-for-profit public option as part of a 4-year transition to get to single-payer in this country,” she said.

The Medicare Transitional Plan reads like a standalone bill that was added to the larger project. But it could also be removed fairly easily and adopted by itself. It is broadly similar to the MICA proposal we published at Shadowproof and is likely similar to the universal Medicare buy-in bill Senator Chris Murphy (D-CT) is expected to release.

The fact that almost no one has paid attention to this section highlights a monumental political development in the release and heavy co-sponsorship of Sanders’ Medicare For All bill.

A few years ago, this section would be dismissed as a fringe leftist proposal. If just this one section was ever approved by Congress, it would be the most progressive health care law in decades.

But right now, it is a mostly overlooked, boring, moderate transitional provision of a much more liberal bill. That puts Gillibrand’s proposal squarely within the mainstream of the Democratic party. And that is just how far and dramatically the debate has shifted.